The chorus of this song refers to Luke 21:36. If Jesus told his disciples to pray this, I figure I should. There are a number of other Bible verses referenced in this song as well.
The doctrine of "eternal security" - at least as it is frequently presented - is one of those pernicious ideas that tend to creep in to the Church from time to time. There are numerous Bible passages that refute it, and yet some seem to insist on clinging to it. I suppose that's because it's comfortable. But what feels comfortable is not always what is true.